Die for making pipe-bends.



DIE FOR MAKING PIPE BENDS. APPLICATION FILED JAN.'26, I9I5 LJOQI. I .y IaIentedSept. 28, 1915,

aj 2 SHEETS-SHEET I.

I C. H. TRUE @L N. T. MCKEE.

DIE FOR MAKING PE BENDS. APPucATmN HL n.26. 1915.'

Annen/Hs Patented 28, 1915.

' ers. superheaters and CHARLES H. TRUE, 0F HAMMOND, INDIANA,

AND NEAL TRIMBLE MCKEE, OF DOBBS FERRY, NEW YORK, ASSIGNORS TO LOCOMOTIVE SUPERHEATER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

DIE ron MAKING PIPE-Barros.

ritmos.

Specification of Letters Patent.

Patented Sept. 28, 1915.

Original application filed April 30, 1914, Serial No. 835,360. Divided and this application filed January 26',

our application Serial No. 835,360 filed April 30, 1914.

Our invention relatesv to dies for making' pipe bends, and more particularly for making what are commonly known as U-shaped bends, when used in connection with boilheating apparatus gene 1ally and exposed to high temperatures, or when used to carry steam or fluids under pressure.

Our invention relates particularly to dies for making bends as aforesaid when the two legs of the bend are required to be very close together. v The object of our invention is to provide dies whereby strong and durable bends of the character aforesaid can be easily and economically produced and at a smallv expense.

A further object of our invention is to provide dies for making bends as specified which bends shall have an internal or free cross-sectional area at all points, fully as great. lit not greater. than that of the individual pipes joined by the bend.

Still a further object of our invention is to provide dies for making bends as aforesaid which, when employed as part of a superheater element of a smoke tube superheater,will not umluly'restrict the iiow ofv at Dobbs Ferry,

Serial No. 4,475.

Aof the .female forming d ie preparatory to having our improved pipe bend formedv thereon; Fig. 2 -is an end view of Fig. 1 with the upper half of the female forming die in position; Fig. 3 is a View similar to Fig. 1, showing the male forming die in positionand the pipes and partially completed pipe bend in section; Fig. 3L is a section taken along the line 31-3 of Fig. 3, part being broken away; Fig. represents a perspective view of the lower half of the female forming die; Fig. 5 represents a perspective view of the lower half of the forging die; Fig. 6 is a plan view showing the pipe bend, partially completed, lying upon the die of Fig. 5; Fig. 7 is a section along the line 7-#7 of Fig. (S exceptthat the upper member of 75 the forging die is shown in position; Fig. 8 is a view, similar to Fig. 6, showing the pipe bend after the forging dies of Fig. 7 have done their work; Fig. 9 is a section taken along the line 9-9 of Fig. 8; Fig. l0 is a plan view of the completed pipe bend; Fig. ll is an edge viewof Fig. l0; Fig. l2 is a section taken along the line lQ-l of Fig. 10; and Fig. 1S is a section taken along the line 13-13 of Fig. .10. i

In the drawings, two pipe lengths l, 2', which are to be united by a pipe bend, are squared off at one end, as at L andclamped between two similar halves 3, 4 of a female forming die. die is shown in Fig. 4: and comprises a. block having-parallel semicircular grooves 5 corresponding to the pipe diameter. The intermediate partition wall or septum between the grooves has one part 6 of the same height as the outer part of the die and another part 7 which rises gradually from a minimum height at the end of the die to a maximum height just before it joins the part 6 which it does by gentle curves which are carried around into the grooves 5. Before placing the pipe lengths in the vdies 3 and 4, their ends are raised to a welding heat. The dies 3 and l must be securely clamped together,`

The lower member 4 of this -90 inner adjacent walls of the pipe ends, its

comparativelT sharp thin edge 13 will slit said walls and raise and lower the slitted wall portions against the parts T belonging to the upper and lower die respectively and compress said slitted portions between the parts 7 and the web 10, which thickens to ard its base so as to conform to the varys ing height of the part 7. If-the dimensions .of the forming dies and of the breeches die are properly chosen, the upper andlower pair of slitted pipe walls will just properly abut with welding' pressure when the edge of the web l() is distant from the end of the part (i of the. septum lying between grooves 5 by substantially the wall thickness of the pipe. A perfect weld will thereby be formed. f

As will be evident from Fig. 3, the web 10 which unites legs 8 has substantially the same'shape as that of the space comprised between the parts 7 and uniting the bores of the female forming die; but this web is smaller in .section thanfsaid space and is everywhere separated from the parts 7 by an amount substantially equal to the wall thickness of the pipes, This separating distance might, however, if desired, be greater at one point and less at another within the scope of the invention, the prime requisite being that the separating space must just take and contain the slitted and spread pipe .walls so as to bring their edges together with the necessary pressure to elect a satisfactory weld. The breeches die is then withdrawn, the forming die opened, and the pipe lengths with the partially completed bend removed. At this stage in the operation, the pipe bend will have the appearance shown in Figs. (S and 7 that is to say, the two pipes will be parallel to one another, and will retain their oiiginal shape at their ends, except 'in the connecting region or yoke between them formed-by the slitted parts of the pipe walls, which have been' raised and lowered respectively and welded together as aforesaid.

It will now be necessary to suitably close the ends of the partially completed bend and at the same time to give said bend a suitable shape. rThese two operations may be' carried out simultaneously as follows: The forging die 15, comprising similar members, is used in any suitable forging machine (not shown) after the manner shown in Fig. 7. The preferred form of the two similar members of this forging die is indicated in Fig. 5 where the one part 1G is scooped out to correspond with the conformation of the completed bend, while another part 17 is recessed by an amount substantially equal to the thickness of the pipe wall. A central recess 1S is provided at one end to receive a slip die 19 which is inserted centrally into the partially formed bend as shown in Fig. (3.

lVith the inclioate pipe bend in position, as shown in Figs. (3 and 7, the forgingl dies are lightly operated so as to effect a pre.- liminary shaping. As soon as the central portion of the bend is flattened 'sufficiently to bind upon the slip die, the latter is withdrawn. The forging operation is then continued until the bend has assumed the appearance shown in Figs. 8 and 9 where, so far as its form is concerned, it is complete except for the lin 21 resulting from the flattening of the surplus wall portions lying outside of the curve which is to form the i outer boundary of the completed bend. The

second pair of forging dies similar to those just described but having no recess 18 for the slip die. This second pair of dies will vthus close the slip die openingl aswell as the remainder of the pipe bend opening. It now remains to remove this n 21 and this we find can be most easily done by using an oXy-acetylene burner andI running around the pipe end at the line of its junction with the lin so as to cut the fin away in any known manner. By then again running the flame around the curved end while projecting it into the plane of separation of the edges, the latter will be welded together in a iirm and durable weld. Or the fin may be cut off by shearing in a suitable trimming press, or the equivalent, before proceeding to weld the edges together.

lnstead'of proceeding' from the incoinplete bend of Fig. 6 through the form of Figs. 8 and 9, z'. e., instead of first compressing the ends s0 as to form the fin 21, and then cutting ofi" said n and welding the edges together., as justdescribed, we may, if we prefer, first shear off all that portion 0f the incomplete bend (Fig. 6) which lies between the eXtreme ends and the curved line b. The edges at said line b may then be brought together by suitable forging dies,

or by other suitable means, and then welded together by the oXy-acetyleneflame as before.

Other methods of bringing the edges (at the curve together or of welding them durably when brought together, may be employed within the spirit of our invention.

By suitably shaping the forming-dies the end c of our improved pipe bend may be formed asa sharp edge' from which the bend gradually widens until it has the full thick- 'ness of the pipes proper when pipes and larger heating surface for the gases to contact with. rlhis groove is, however, not essential to the practice of our invention and may be omitted. Indeed, the forni and pro portions of the bend may be varied widely without departingfroni the spirit ofthe invention and the section through the bend (as shown in Fig. 13) may have any desired and convenient fo-rm.

The cross-sectional area of the passage through the pipe bend, at allpoints thereof, ca n obviously be fully as great. as that of the pipe itself, and as much greater as may bedesired. This is accomplished by choosing a suitable length and thickness for the web 10 and by correspondingly dimension- Iing the forming dies with which the web must coperate.

When the pipe bend, made as above described, is completed (Figs. lll-12) it is practically impossible to find the welds, so perfectly and smoothly are the edges unitef. In particular, there will be no fins projecting inwardly from the welds; such fins `occur in certain other methods of pipe bend manufacture and are very difficult if ynot impossible to remove. If left in place such fins will restrict the passage and produce a lack of uniformity among different bends as well as inefficiency in individual bends.

V The slip die, while preferred by us, is not essential to the practice of our invention.

Changes in the exact form of the various dies, and in the details of the operations employed in shaping the bends and making the welds, may be made within the spirit of our invention as defined in 'l the following claims.

We claim.:

l. A die for making pipe bends compris- 'ing a female forming die having parallel bores for holding two pipe lengths said bores being joined by a space opening from one end of the die, and a breeches die having two legs forV entering said bores, said legs being united by a web shaped to correspond. with the space referred to but spaced from the walls of said space.

2. A die for making pipe bends comprising a female forming die having parallel bores for holding two pipe length said bores being joined by a space opening from one end of the die and tapering to a closure before the other end is reached, and a breeches die having two legs for entering said bores, said legs being' united by a web shaped to correspond with the space referred to but separated from the walls of said space by an amount substantially equal to the thickness of the pipe walls.

3. A die for makingpipe bends comprising a. female forming die having parallel bores. forholding two pipe lengths said bores being joined by aspace opening from one end of the die and ending before the other end is reached, and a breeches die hav ing two legs for entering said bores, said legs being united by a web shaped to correspond with the space referred to but spaced from the walls of said space.

4. A die for making pipe bends compris-y ing a female forming die having parallel bores for holding two pipe lengths said bores being joined by a. space opening from one end of the die and ending before the other end is reached, and a male die having a cutting member. adapted to be pressed into the female die against the end of neighboring walls of the 'two pipes so as to slit and spread said walls against the opposite walls of the space joining the two bores.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

oHARLHs H. TRUE.' NEAL TRIMBLE Menen.

lNitnesses as to C. H. True: THOMAS PHILLIPS, CLYDE B. LA'rHnor. Witnesses as to N. T. McKee:

JAMES K. SCOTT, JOHN A. BARNES. 

